1. Field of Invention
The present invention relates to a turbine, and more particularly to a wind turbine comprising a rotor hub which has a peripheral guiding rim adapted for guiding a flow of air to a plurality of blades so as to maximize an efficiency of the wind turbine.
2. Description of Related Arts
Wind is the movement of air, which has mass, and when air is in motion it contains kinetic energy. A wind energy system converts the kinetic energy of wind into mechanical or electrical energy that can be harnessed for practical use. Mechanical energy harnessed by windmills, for example, can be used for tasks such as pumping water for a well.
Wind energy systems which harness electrical energy are generally referred to as wind turbines. As air flows past the rotor of a wind turbine, the rotor spins and drives the shaft of an electrical generator to produce electricity. The electricity generated by a wind turbine can be collected and fed into utility power lines, where it is mixed with electricity from other power plants and delivered to utility customers.
The output of a wind turbine depends on a number of factors, including the turbine's size and design, the speed of wind passing through the rotor, and the amount of time that wind is available. The energy that wind contains is a function of the cube of its speed. This means that a site with 12-mph average winds has more than 70% more energy than a site with 10-mph average winds.
Wind turbines generally consist of blades that rotate around a hub, which most commonly revolves around a horizontal axis. The hub is connected to a drive train, which transfers energy to a generator, often via a gearbox. The drive train and gear box are typically located inside a nacelle or housing, which is generally mounted at the top of a tower.
A major problem for this kind of conventional wind turbine is that when air flows through the turbine, a substantial portion of which will be bounced back by the hub. As a result, that portion does not contribute to the rotational movement of the turbine. At a given time, much energy which is carried by wind will be lost simply by it not being properly collected. What is worse is that if the energy carried by that portion of wind which impinges on the turbine but is not properly converted into kinetic energy of the hub and the blade, the excess energy will actually cause air drag and retard the rotational movement of the wind turbine, thereby significantly reducing an efficiency thereof.